A reinforcing bar binder is comprising a binding line feed mechanism for feeding out a binding line of a wire or the like wound around a reel to be wound around a reinforcing bar, and a binding line twist mechanism for twisting the binding line wound around the reinforcing bar to bind, and the binding line feed mechanism and the binding line twist mechanism are successively operated by trigger operation to carry out binding operation of 1 cycle.
When a circular arc shape nose of the reinforcing bar binder is hung around the reinforcing bar and a trigger lever is pulled, the binding line is fed out around an inner peripheral face of a nose by the binding line feed mechanism to form a biding line loop at a surrounding of the reinforcing bar, a rear end of the binding line loop is cut by a cutter mechanism, a pair of hook type hooks of the binding line twist mechanism are closed to grasp the binding line loop to thereafter rotate and the binding line loop is twisted to bind the reinforcing bar.
The reinforcing bar binder of a prior art is constituted to turn the binding line around the reinforcing bar by two rotations or more and catch a middle portion of the binding line loop remote from a front end and a rear end thereof by the pair of hooks and this is because when portions of the binding line at a vicinity of the front end or the rear end is caught, in rotating the hooks, the front end or the rear end is drawn out from the hooks to disengage the loop and binding cannot be carried out. Therefore, lengths of both end portions of the binding line extended from the portion grasped and twisted by the hooks are prolonged, the portions are projected at the surrounding of the reinforcing bar to bring about a drawback that the binding line is projected from a surface of concrete when concrete is cast and also an amount of consuming the binding line is large.
Further, the reinforcing bar binder of the prior art poses a problem that the amount of consuming the binding line is large since the binding line is turned around the reinforcing bar by two rotation or more and the length of the binding line to be fed out is constant regardless of the diameter of the reinforcing bar. Further, when the diameter of the reinforcing bar is small, an amount of twisting the binding line is increased, a long time period required for twisting is taken, the binding line cannot sufficiently be tightened and a restraining force may become insufficient. Further, since the length of the twisted portion is long, when concrete is cast, the binding line may be projected from the surface of the concrete to thereby cause a problem in finishing.
Further, according to the reinforcing bar binder of the prior art, when the nose in the circular arc shape of the reinforcing bar binder is hung to the reinforcing bar and the trigger lever is pulled, the binding line is fed out along a guide groove of an inner peripheral face of the nose by the binding line feed mechanism. The nose is provided with a forming portion opposed to the guide groove, the binding line is brought into contact with the forming portion when moving forward along the guide groove to curl to thereby form a loop around the surrounding of the reinforcing bar. Further, the binding line is cut by a binding line cut apparatus at a front end portion of the nose, the pair of hook type hooks of the binding line twist mechanism are closed to grub the binding line loop to thereafter rotate and twist the binding line loop to bind the reinforcing bar.
According to the reinforcing bar binder of the prior art, since the binding line is fed out bypassing an interval between the guide groove of the nose and the forming portion opposed to the guide groove, when the binding line cut apparatus is not arranged at the vicinities of the binding line twist mechanism and the forming portion, the binding line loop cannot be twisted by constituting a hindrance by the forming portion disposed on an inner side of the binding line loop. Further, when the binding line cut apparatus is arranged at the vicinity of the forming portion, since the binding line cut apparatus is disposed at a position remote from the binding line twist mechanism, an extra portion from a point of grasping the binding line to a terminal end portion of the loop is long, further, since the binding line needs to be wound around the reinforcing bar by two turns or more, there poses a problem that the amount of consuming the binding line is large and an outlook thereof in finishing to bind is poor. Further, even when the binding line cut apparatus is arranged at the vicinity of the forming portion, there is a case in which the binding line is caught by the fixed forming portion in twisting the binding line to give an unpleasant feeling to an operator.